title: Relationships between the metabolism of high-density and very-low-density lipoproteins in man: studies of apolipoprotein kinetics and adipose tissue lipoprotein lipase activity.
abstract: In order to gain further insight into the relationship between high-density lipoprotein (HDL) metabolism and plasma triglyceride transport, measurements were made of HDL cholesterol concentration, apoprotein (apo) AI and AII metabolism, very-low-density-lipoprotein (VLDL) apo B metabolism, and heparin-elutable adipose tissue lipoprotein lipase (LPL) activity in seventeen subjects with a wide range of plasma triglyceride concentrations (0.8-25 mmol/l). The fractional catabolic rate (FCR) of VLDL apo B was directly related to LPL activity (r = +0.80), providing evidence that the activity of the enzyme in adipose tissue is a determinant of the rate of lipolysis of VLDL in man. HDL cholesterol concentration was a positive function of both VLDL apo B FCR (r = +0.74) and LPL activity, a finding consistent with previous evidence for the origin of a proportion of HDL cholesterol from 'surface remnants' liberated during VLDL catabolism. THe FCRs of both apo AI and apo AII were inversely related to VLDL apo B FCR (AI, r = -0.52; AII, r = -0.69) and to LPL activity. The synthetic rate of ap AII, but not that of apo AI, was positively correlated with VLDL apo B synthesis (r = +0.7 1). Thus, the metabolism of the major proteins of HDl in man appears to be closely associated with VLDL metabolism.
mesh_terms: D000273:Adipose Tissue / Q000201:enzymology*; D000328:Adult; D016632:Apolipoprotein A-I; D016633:Apolipoprotein A-II; D001053:Apolipoproteins / Q000096:biosynthesis / Q000097:blood*; D001054:Apolipoproteins A; D001055:Apolipoproteins B; D005260:Female; D006801:Humans; D007700:Kinetics; D008071:Lipoprotein Lipase / Q000378:metabolism; D008075:Lipoproteins, HDL / Q000097:blood*; D008079:Lipoproteins, VLDL / Q000097:blood*; D008297:Male; D008875:Middle Aged
chemical_list: D016632:Apolipoprotein A-I; D016633:Apolipoprotein A-II; D001053:Apolipoproteins; D001054:Apolipoproteins A; D001055:Apolipoproteins B; D008075:Lipoproteins, HDL; D008079:Lipoproteins, VLDL; D008071:Lipoprotein Lipase